Automatic photographic apparatus for a camera

ABSTRACT

A photographic camera wherein the needle of the light meter is scanned to serve as a means for determining the setting of the shutter and diaphragm units during operation in daylight. A resistor which is variable by the focusing member of the camera is connected in circuit with the light meter when the camera is used for operation in artificial light. The connection of the variable resistor into the light meter circuit, in addition to or as a substitute for a photosensitive receiver, can take place in response to attachment of a source of artificial light or automatically when the intensity of scene light is below a predetermined value.

United States Patent AUTOMATIC PHOTOGRAPHIC APPARATUS FOR A CAMERA 10Claims, 6 Drawing Figs.

US. Cl 95/10 CE, 95164 C Int. Cl G03b 7/08, G03b 7/ 16 Field of Search95/10 C,

11.5,64R, 64 C,53 R, 53 E, 10 CE, IOCT, 10CD Primary Examiner-Joseph F.Peters Attorney-Michael S. Striker ABSTRACT: A photographic camerawherein the needle of the light meter is scanned to serve as a means fordetermining the setting of the shutter and diaphragm units duringoperation in daylight. A resistor which is variable by the focusingmember of the camera is connected in circuit with the light meter whenthe camera is used for operation in artificial light. The connection ofthe variable resistor into the light meter circuit, in addition to or asa substitute for a photosensitive receiver, can take place in responseto attachment of a source of artificial light or automatically when theintensity of scene light is below a predetermined value.

PATENTED JAN 41972 3,631,778

sum 1 [IF 3 T7: -26b 47 26c INVENTOR.

BY V. ALBEDYLL KARL WAGNER HANS PETER HUBER PATENTED JAN 4 i872 SHEET 2BF 3 I IIIIIIIIIIIJIIJIIII[III/III Fig.4

IN V EN TOR.

y JOACHIM V. ALBEDYLL KARL WAGNER HANS PETER HUBER SHEET 3 OF 3 123 mIQUQFWHW 12w? vol 409 m IN VEN TOR.

By JOACHIM v.ALBEDYLL KARL WAGNER HANS-PETER HUBER 1 "AUTOMATICrno'roommc Arrxnx'rus son A CAMERA BACKGROUND OF THE INVENTION Thepresentinvention relates to photographic apparatus for use indaylightand artificialli'ght. More particularly, the invention relates toimprovements in photographic apparatus wherein shutter unit and/or thediaphragm unit'is adjusted automatically 'as a. function'of scenebrightness during operation in daylightyand whereinat least one of theseunits is automatically adjusted when the apparatus is used with amultiple flashb'ulb liolder,'an electronicfia'sh or another built-in orseparable source of artificial lightl Still more particularly, theinvention relates to improvements in cameras wherein the exposure valueor values can be "influenced by the focusing means during operation inartificial light.

SUMMARY OF THE INVENTION An object of the inventionis to provide aphotographic apparatus wherein the exposure control is automaticallyadjusted in response to setting for operation in daylight or artificiallight and wherein the exposure values for'operation in artificial lightare automatically selected in a way to insure the making of satisfactoryexposuresat several distances from the subject.

'Another object of the invention is to provide an exposure control whosesetting is altered'automatically when the intensity of scene light risesabove or decreases below a predetermined value.

A further object of the invention is to provide a novel electric circuitfor the exposure controls of cameras which are to be used indaylight orartificial light.

The invention is embodied in a photographic apparatus which is designedfor use in daylight or artificial light. The apparatus comprisesadjustable diaphragm and shutter units,

light meter means having output means movablebetween' a plurality ofpositions, adjusting means providing an operative connection between thelight meter means and at least one of the units to adjust the latter asa function of the position of the output means, variable resistor means,focusing means movable between a plurality of positions each of whichisindicative of a different distance from the subject and being arrangedto adjust the resistor means as a function of its selected position, andan electric circuit arrangement which includes the light meter means andfurther includes photosensitive receiver means in circuit with the lightmeter means to determine the position of the output means as a functionof the intensity of scene light, at least when theapparatus is used indaylight. The circuit arrangement further includes an auxiliary circuithaving switchover means operable to move from a first to a secondposition in which the resistor means is respectively disconnected fromand in circuit with the light meter means, and operating means foroperating the switchover means, at least when the intensity of scenelight is below a predetermined value, so' that the resistor means theninfluences the position of the output means.

The operatingmeans mayinclude the footor another portion of a source ofartificial light which causes the switchover means to change itsposition in response to movement of such portion to anoperative positionin which the apparatus can make an exposure with flash. Alternatively,the operating means may include-secondphotosensitive receiver means andelectromagnet means whose condition of energization is changed when theintensity of scene light to which'the second receivermeansis exposed isbelow the predetermined value whereby the electromagnet meansefi'ectsthe aforementioned change in position of the "switchover means.The latter preferably includes a two-way switch.

In accordance with another feature of the invention, the resistance ofthe variable resistor means (or of further resistor means which isconne'ctable in the circuit of the light meter means together with thevariable resistor means) can be selected in such a way'that it isindicative of the guide number of the source of artificial light whichis tobe used with the apparatus.

The novel features which are considered as characteristic/bf theinvention are set forth" in" particular in-the appended claims. Theimproved photographicapparatus itself;however, both as to itsconstructionand its mode of operation,*togeth'er with additionalfeatures and advantagesthereofi will b best understood upon perusal ofthefollowing detaileddesciiption of certain specific embodimentswithreference to the 'accompanying drawings.

BRIEF DESCRIPTION OF 'I'HEDRKWINGS FIG. 1 is a fragmentary schematiclongitudinal verticalsectional view of a still camera which embodies oneform of the invention;

FIG. 2 is a diagram of the electric circuit arrangement in the camera ofFIG. 1;

FIG. 3 is a fragmentary schematic longitudinal vertical-sectional viewof a second still camera;

FIG. 4 is a diagram of the electriccircuit arrangement'inthe camera ofFIG. 3;

FIG. 5 is a fragmentary schematiclongitudinalvertical-sectional view ofa third camera; and

FIG. 6 is a diagram of the electric circuit arrangement the camera ofFIG. 5.

DESCRIPTION OF TI-IE PREFERRED EMBODIMENTS FIG. 1 illustrates a portionof astill camera having a housing H accommodating a reciprocal camerarelease 2"bia'sed by a return spring 1. The release 2 is a slidewhich isprovided with anactuating portion or trip' 3 serving toclose a normally"open electric switch 4. Still further, the release 2 comprises aprojection or lug 5 which nonnallyengagesan'arni Tpro'videdon a scanningmember 6; The latter is biased'by a spring 8 which is weaker thanthespring l and'tendsto"movethescanning member 6 downwardly,as'viewedinFIG. 1."A' pin" 9"on a downwardly extending "elongated-"arrn 6a"of 3 the scanning member 6 is received in a slot 10a provided in aringsli aped setting member 10 of the adjustablediaphragm*unit. Thescanning member 6 is 'provided'w'ith a serrated scanning face 11 whichcan engage-the output 'member or' needle "12 bf a light meter 13. Theneedle 12 is turnable OrreciprocaI aIong' a back support or anvil 14.*When the release 2"-mo'ves downwardly, the spring 8 is'free tocontractso as to movethe scanning face 11 into engagement-with theneedle 12 andto press the latter against the back support 14. Theposition of the scanning member 6, and hencethe position ofthe settingmember 10 is then a function of the position of the needle 12.

The camera further comprises asecond scanning member 15 which is biaseddownwardly by a helical-spring-l6 and has a follower post 17 which bearsagainst the upper edgeofthe scanning member 6. The second-scanningme'r'nber'lS is provided with a serrated scanningface' l8 and itsdownwai'dly extending elongated arm 15a carries a pin 19 'exte'ndingintoa slot 20a provided in the ring-shaped settingmember '20 of anadjustable shutter unit. The arm'lSa' has a projection ZI whi'ch can beengaged by-the pallet of a-blo'cking lever23pivotable on a fixed pin 22and-biased by a'spring24which tendsto move the pallet away fromengagement with theprojection 21. The blocking lever 23 constitutes "thearmature ofanelectromagnet 25 which isenergizable to thereby move thelever into engagement with the projection 2i. Theupper arm ofthe lever23 constitutes an actuating member or trip for themedian contact-26c ofa switchover-device here shown as'a twoway switch 26 whose fixedcontacts 26a,"26b flank*thernovable contact 26c.

The camera also comprises a'ring-shaped focusing member 27 having twomanually engageable' milled or knurled portions 27a, 27b which enablethe operator to rotatethe focusing member in directions indicatedby'the"doubleheaded arrow A-B. The focusing member 27 has a 'masking'portiom formed with a tapering slot28 which is movable'infront of a"fixedly mounted photosensitive receiver 29. The focusing member 27further includes a slider 30 which constitutes the movable part of avariable resistor 31.

The top wall of the housing H supports an indexible socket 32 for thebase 33 of a source of artificial light here shown as a multipleflashbulb holder F, preferably the one commonly known as Flashcube. Aplunger 34 extends into the socket 32 from below and is depressed whenthe plug 330 of the base 33 is properly introduced so that the holder Fis indexible with the socket. The direction in which the plunger 34 ismoved in response to attachment of the holder F is indicated by thearrow C. A helical spring 35 biases the plunger 34 upwardly; when theholder F is attached to the socket 32, the lower end of the plunger 34closes a nonnally open switch 36.

The circuit arrangement of the camera of FIG. 1 is illustrated in FIG.2. The circuit arrangement includes a battery 40 or another suitableenergy source. The two-way switch 26 can connect the battery 40 with asecond photosensitive receiver 41 or with the aforementioned variableresistor 31 whose resistance is variable by the focusing member 27.Thus, the angular position of the needle 12 of the light meter 13 iseither a function of the resistance of the photosensitive receiver 41 ora function of the resistance of the variable resistor 31. If theswitches 4 and 36 are closed, the battery 40 is connected in circuitwith an auxiliary circuit which includes the electromagnet 25, thephotosensitive receiver 29, as well as two transistors 42, 43 and theassociated fixed resistors 45, 46, 47 and 48. The parts 42, 43, 45, 46,47 form a switching circuit which is controlled by a voltage dividerincluding the aforementioned photosensitive receiver 29 and a fixedresistor 44. The collector circuit of the transistor 42 contains theelectromagnet 25 for the blocking lever 23.

The scanning members 6 and constitute an adjusting device whichestablishes an operative connection between the diaphragm unit (settingmember 10) and shutter unit (setting member 20) on the one hand, and thelight meter 13 on the other hand so that the two units are adjusted as afunction of the position of the needle 12 when the camera is used indaylight.

The Operation:

If the user wishes to make an exposure with flash at a time when thescene brightness is rather high, the holder F is attached to the socket32 so that the plunger 34 closes the switch 36. Since the photosensitivereceiver 41 is in circuit with the light meter 13, the angular positionof the needle 12 is indicative of the scene brightness. The user thendepresses the release 2 so that the trip 3 closes the switch 4 and thelatter connects the auxiliary circuit including the transistors 42, 43and the resistors 45-48 with the battery 40. If the scene brightness issuch that the resistance of the second photosensitive receiver 41exceeds a predetennined value, the auxiliary circuit preventsenergization of the electromagnet 25 so that the scanning members 6,respectively adjust the diaphragm unit and the shutter unit as afunction of scene brightness which is indicated by the position of theneedle 12, i.e., as a function of the resistance of the photosensitivereceiver 41. The flashbulb which faces the subject is fired on openingof the shutter unit; such opening can be effected by the release 2 inresponse to movement to its lower end position. Light issuing from thefired flashbulb serves to effect additional illumination of the subject.

If the exposure is made when the intensity of scene light is below apredetermined value, the resistance of the receiver 29 is rather highand the potential at the base of the transistor 43 suffices to changethe condition of the auxiliary circuit so that the latter permitsenergization of the electromagnet 25 when the user closes the switch 4while the socket 32 accommodates the base 33 of a multiple flashbulbholder F. The energized electromagnet 25 pivots the blocking lever 23whereby the latters pallet pivots in the direction indicated by an arrowD and intercepts the projection 21 to thus insure that the settingmember selects an exposure time which is acceptable for exposures withflash. At the time, the upper arm of the lever 23 moves the contact 26cof the two-way switch 26 against the fixed contact 26b so that thereceiver 41 is disconnected. The light meter 13 is then connected inseries with the variable re- .sistor 31. Thus, the angular position ofthe needle 12 is a function of the selected resistance of the resistor31, i.e., a function of the position of the focusing member 27. Thelever 23 does not interfere with downward movement of the scanningmember 6 so that the setting member 10 selects an aperture size which isa function of the distance from the subject. As mentioned above, thesecond scanning member 15 can descend only to the extent pennitted bythe pallet of the lever 23 which then extends into the path of movementof the projection 21.

The provision of the tapering slot 28 in front of the photosensitivereceiver 29 constitutes an advantageous feature of the just describedcamera. The masking portion which is formed with this slot is movable infront of the receiver 29 in dependency on the selected position of thefocusing member 27, i.e., as a function of the distance from thesubject. When the camera is moved closer to the subject, the amount oflight issuing from the flashbulb in response to firing prevails over theremaining light so that it is desirable to fire the bulb earlier whenthe distance between the camera and the subject is less. The slot 28reduces the amount of scene light which reaches the receiver 29 inresponse to rotation of the focusing member 27 in a direction which isindicative of a reduced distance from the subject so that the switchingcircuit can react earlier.

The electromagnet 25 and the photosensitive receiver 29 constitute anoperating means in the auxiliary circuit of the arrangement shown inFIG. 2, and such operating means serves to change the position of theswitchover device (two-way switch 26) when the intensity of scene lightis below a predetermined value whereby the switch 26 connects thevariable resistor 31 in circuit with the light meter 13 so that theresistor 31 influences the position of the needle 12 in dependency onselected position of the focusing member 27.

The electromagnet 25 can be replaced by two discrete electromagnets oneof which is energizable to pivot the lever 23 and the other of which isenergizable to change the position of the movable contact 260 in thetwo-way switch 26.

The resistance of the variable resistor 31 is indicative of the guidenumber of the multiple flashbulb holder.

In the camera of FIG. 3, the release 54 is biased by a return spring 55which tends to maintain the release in the illustrated startingposition. The release 54 is provided with a trip 56 which can close anormally open switch 57 and with a projection or lug 58 cooperating withthe arm 59 of a scanning member 60 having a serrated scanning face 62. Ahelical spring 61 biases the scanning member 60 downwardly, as viewed inFIG. 3, so that the arm 59 bears against the projection 58 when therelease 54 assumes the illustrated starting position. The light meter isshown at 63 and its output member or needle at 64. The latter is movablealong a back support 65. An elongated downwardly extending arm 60a ofthe scanning member 60 is provided with a pin 66 extending into a slotprovided in a ring-shaped setting member 67 of the diaphragm and shutterunits. The setting member 67 is provided with a cam 68 which is trackedby a pin-shaped follower 71 provided on a lever 70 which is pivotable ona pin 69. The lever 70 directly controls the retard mechanism (notshown) of the shutter unit. A portion of the face on the cam 68 ispreferably designed in such a way that, when this portion is engaged bythe follower pin 71 and the setting member 67 rotates in response todisplacement of the scanning member 60, the angular position of thelever 70 remains unchanged. Thus, the angular position of the settingmember 67 must be changed to a predetermined extent before the lever 70begins to adjust the retard mechanism. A blocking member 72, here shownas a two-armed lever, is pivotable on a pin 73 and is biased by ahelical spring 74. This blocking lever 72 constitutes the armature of anelectromagnet 75 and turns in the direction indicated by arrow B whenthe electromagnet is energized. Such energization of the electromagnet75 enables the blocking lever 72 to prevent movements of the lever 70.The aforementioned configuration of the first portion of the face on thecam 68 enables the blocking lever 72 to intercept the lever 70 beforethe latter can change the setting of the retard mechanism during initialrotation of the setting member 67, i.e., immediately after closing ofthe switch 57.

The housing 76 of the photographic camera shown in FIG. 3 carries anaccessory shoe 77 which can receive the foot (not shown) of anelectronic flash unit whereby the foot depresses a plunger 78 which isbiased into the space between the rails of the shoe 77 by a helicalspring 79. Depression of the plunger 78 in response to attachment of anelectronic flash results in closing of a normally open switch 80 andcauses the movable median contact 810 of a two-way switch 81 to moveaway from a first fixed contact 81!) and to engage a second fixedcontact 81a.

The electric circuit arrangement of the camera shown in FIG. 3 isillustrated in FIG. 4. It comprises a battery 88 and a photosensitivereceiver 85 which is in series with the battery 88 and with the lightmeter 63. During operation in daylight, the position of the needle 64 ofthe light meter 63 is a function of the resistance of the receiver 85which is exposed to scene light. This receiver 85 is then connected inparallel with seriesconnected fixed corrective resistors 86, 87. Whenthe camera is set for operation with flash, the resistor 87 is replacedwith a variable resistor 89 through the intermediary of the two-wayswitch 81 wherein the movable contact 810 then engages the contact 81a.The variable resistor 89 is then in series with the resistor 86.

The auxiliary circuit of the circuit arrangement shown in FIG. 4comprises two transistors 90, 91 controlled by a voltage dividerincluding a second photosensitive receiver 92 and a fixed resistor 93.The center tap of the voltage divider is connected with the base of thetransistor 91. The emitters of the transistors 90, 91 are connected to acommon emitter resistor 94. The auxiliary circuit further includes fixedresistors 95, 96 and 97. The electromagnet 75 is connected in thecollector circuit of the transistor 90.

The Operation:

To make an exposure, the user depresses the release 54 in the directionindicated by arrow. If the shoe 77 is empty, the auxiliary circuitincluding the transistors 90, 91 is open because the switch 80 is openand the angular position of the needle 64 is then a function of theresistance of the photosensitive receiver 85, i.e., the exposure timeand the aperture size are selected strictly as a function of scenebrightness. As the release 54 moves downwardly, the spring 61 is free tocontract and the scanning member 60 travels toward the back support 65until its scanning face 62 engages the needle 64. The setting member 67rotates in a counterclockwise direction until the face 62 reaches theneedle 64. The lever 70 adjusts the retard mechanism of the shutter unitto the extent determined by the position of the face on the cam 68 withreference to the follower 71 when the scanning member 60 terminates itsmovement under the action of the spring 61. The setting member 67further adjusts the diaphragm unit so that not only the exposure timebut also the aperture size is a function of scene brightness whenthecamera is used in daylight.

If the user inserts the foot of a flash into the shoe 77, the plunger 78moves downwardly and closes the switch 80 by simultaneously changing theposition of the two-way switch 81 so that the latter disconnects theresistor 87 and connects the resistor 86 in series with the variableresistor 89. The resistor 89 is adjustable by the focusing member (notshown), preferably in the same way as described in connection with thefocusing member 27 and resistor 31 of FIG. 1.

Since the switch 57 closes in response to depression of the release 54,the auxiliary circuit including the transistors 90, 91 is completedbecause the plunger 78 holds the switch 80 in closed position. If theintensity of scene light is low, the resistance of the receiver 92 ishigh and the potential at the base of the transistor 91 suffices toeffect a change in the condition of the auxiliary circuit so that theelectromagnet 75 is energized and pivots the blocking lever 72 againstthe opposition of the spring 74 (arrow B in FIG. 3) whereby the palletof the blocking lever 72 intercepts the follower 71 or another part ofthe lever 70 and prevents a change in adjustment of the retardmechanism. Thus, the cam 68 cannot influence the setting of the shutterunit; this shutter unit then assumes a' position in which it can furnishan optimum time for making of an exposure with artificial illuminationof the subject.

The setting member 67 then merely adjusts the diaphragm in dependency onthe selected distance from the subject (variable resistor 89).

FIG. 4 shows that the photosensitive receiver remains in the circuit atall times, i.e., also when the exposure is made with artificialillumination of the subject. Consequently, the aperture size foroperation with flash is selected not only a function of the distancefrom the subject (resistor 89) but also as a function of the intensityof scene light prior to firing of the flash. The purpose of the resistor87 is to insure that the conditions influencing the light meter 63during operation in daylight are equivalent or substantially equivalentto conditions during operation with flash.

When the camera of FIGS. 3 and 4 is used with a source of artificiallight, the photosensitive resistor 85 influences the setting of thediaphragm unit as a function of the lightness or darkness of the areasurrounding the subject. The variable resistor 89 influences the settingof the diaphragm unit as a function of the position of the focusingmember.

The plunger 78 of FIG. 3 can be said to form part of the source ofartificial light. When permitted to assume the illustrated inoperativeposition, the plunger 78 v maintains the switchover means (two-wayswitch 81) in a first position which the variable resistor 89 isdisconnected from the light meter 63. When the push rod 78 is caused toassume its operative position (in response to insertion of a foot intothe accessory shoe 77), the plunger changes the position of the two-wayswitch 81 to thereby connect the resistor 89 in circuit with the lightmeter 63, i.e., in parallel with the photosensitive receiver 85.

The mechanical details of the camera shown in FIG. 5 are quite similarto those of the camera shown in FIG. 3. The release 101 is biasedupwardly by a strong return spring 102 and carries a trip 103 which canclose a normally open switch 104. A projection 105 of the release 101cooperates with an arm 107 of a reciprocable scanning member 106 whichis biased downwardly by a helical spring 108 and has a serrated scanningface 109. The light meter 111 has an output member or needle which canbe engaged by the face 109 and urged against a back support 112. Anelongated arm 106a of the scanning member 106 is provided with a pin 113extending into the slot of a ring-shaped setting member 114. The latteris provided with a earn 115 tracked by the follower pin 118 of atwo-armed lever 116 which is fulcrumed at 117 and adjusts the retardmechanism (not shown) of the shutter unit. The foremost or outennostpart of the face on the cam 115 has a curvature whose center is locatedon the axis of the setting member 114 so that the follower 118 does notpivot the lever 116 during the initial stage of rotation of the member114 from its starting position. A blocking lever 120 is pivotable on apin 121 and is biased to inoperative position by a helical spring 122.The lever 120 constitutes the armature of an electromagnet 119 which isenergizable to move the pallet of the lever into the blocking engagementwith the follower 118. The lever 120 then displaces a push rod which canactuate a battery of switches 131, 132, 133. When the electromagnet 119is deenergized, the switch 131 is open, the switch 133 is closed, andthe movable contact 132:: of the switch 132'engages the upper fixedcontact 1320. On energization of the electromagnet 119, the lever 120causes the push rod 130'to close the switch 131, to open the switch 133,and to move the movable contact 132c into engagement with the otherfixed contact 132b of the switch 132.

The top wall of the housing of the camera shown in FIG. 5 carries anaccessory shoe 123 which normally accommodates the tip of a plunger 124biased upwardly by a helical spring 125. The lower end of the plunger124 closes a normally open switch 126 when the shoe 123 receives thefoot of a flash unit.

The circuit arrangement of the just-described camera is illustrated inFIG. 6. This circuit arrangement includes a battery or an analogoussource 136 and an auxiliary circuit here shown as a bridge circuitincluding a first branch containing a photosensitive receiver 137 and afixed resistor 138. A second branch of the bridge circuit contains aresistor 139 which is variable by the focusing member, not shown, and afixed resistor 140. The fixed resistor 140 is disconnected from thevariable resistor 139 in response to opening of the switch 133. Thebridge circuit is connected with the battery 136 in response to closingof the switches 104 and 126, i.e., when the shoe 123 accommodates thefoot of a flash unit and when the release 101 is caused to leave itsillustrated starting position. A diagonal branch of the bridge circuitcontains the base-emitter circuit of a transistor 141 having a collectorresistor 142.

The light meter 111 is connected with a photosensitive receiver 143 orwith the variable resistor 139, depending on the position of the movablecontact 1320 in the two-way switch 132. The collector of the transistor141 is connected with the base of an amplifier transistor 144. Theelectromagnet 119 is connected in the collector circuit of thetransistor 144. The emitter and the collector of the transistor 144 canbe shunted by the switch 131; when the switch 131 is closed, theelectromagnet 119 is connected in series with the battery 136 inresponse to closing of the switch 104.

An advantage of the just-described circuit arrangement is that theprevailing scene brightness, determined by the photosensitive receiver137, can be directly compared (by transistor 141) with the resistance ofthe variable resistor 139. The latter is adjustable by the focusingmember. The bridge circuit can automatically determine which of the twoaperture sizes is smaller, namely, the aperture size which is a functionof the resistance of the receiver 137 (dependency on scene brightness)or the aperture size determined by the resistor 139 in dependency on theposition of the focusing member. The switch 126 shown in FIG. 6 is open;therefore, the circuit is assumed to be ready for making an exposurewithout artificial illumination of the subject. The photosensitivereceiver 143 is in series with the light meter 11 1 because the movablecontact 132c of the two-way switch 132 engages the fixed contact 1320.The camera can make an exposure with automatic selection of aperturesize and exposure time. The aperture size is determined by the settingmember 114 in a manner well known from the art. The exposure is madeupon depression of the release 101 whereby the scanning member 106detennines the angular position of the setting member 114 to fix theappropriate exposure time (via lever 116) and aperture size (via settingmember 114). The shutter can be released when the release 101 reachesits lower end position.

If the user wishes to make an exposure with artificial illumination ofthe subject, the foot of a flash unit (not shown) is introduced into theshoe 123 whereby the plunger 124 closes the switch 126. When the release101 is thereupon depressed to close the switch 104, the bridge circuitis connected with the battery 136. If the intensity of scene light israther high, i.e., if the resistance of the photosensitive receiver 137is low, the condition of the transistor 141 does not change and theelectromagnet 119 remains deenergized. Thus, the photosensitive receiver143 remains connected with the light meter 111 and the shutter isadjusted as a function of the position of the scanning member 106 whenthe latter's face 109 engages the needle 110. The flash unit producesartificial light which serves for additional illumination of thesubject.

However, when the scene brightness is such that the aperture sizedetermined by the resistance of the resistor 139 as a function of theposition of the focusing member is smaller than the aperture sizedetermined by the resistance of the photosensitive receiver 137, thebridge circuit causes the transistor 141 to change its condition and toefi'ect energization' of the electromagnet 119 by way of the amplifiertransistor 144. The blocking lever 120 then holds the follower 118 so asthat the shutter unit furnishes an optimum exposure time for operationwith flash. The blocking lever 120 also displaces the push rod 130 toefiect opening of the switch 133 and to thus disconnect the fixedresistor 140 from the variable resistor 139. The movable contact 1320 ofthe two-way switch 132 engages the fixed contact 132b so that thephotosensitive receiver 143 is disconnected from the light meter 111 andthe latter is connected with the variable resistor 139. Opening of theswitch 133 would affect the balance of the bridge circuit and wouldtherefore cause deenergization of the electromagnet 119. This isprevented by the switch 131 which is closed. simultaneously with openingof the switch 133 so that the electromagnet 119 is then connecteddirectly with the battery 136 and remains energized as long at therelease 101 is held against return movement to the illustrated startingposition, i.e., as long as the switch 104 remains closed.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that other can, by applying current knowledge,readily adapt it for various applications without omitting featureswhich fairly constitute essential characteristics of the generic andspecific aspects of my contribution to the art.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended:

1. In a photographic apparatus for use in daylight and artificial light,a combination comprising adjustable diaphragm and shutter units; lightmeter means having output means movable between a plurality ofpositions; adjusting means providing an operative connection betweensaid light meter means and at least one of said units to adjust thelatter as a function of the position of said output means; variableresistor means having a resistance indicative of the guide number of thesource of artificial light which is to be used with the apparatus;focusing means movable between a plurality of positions each of which isindicative of a difierent distance from the subject and arranged toadjust said resistor means as a function of the selected positionthereof so that the resistance of the thus adjusted resistor means isindicative of the position of said focusing means and of said guidenumber; and an electric circuit arrangement including said light metermeans and further including photosensitive receiver means in circuitwith said light meter means to determine the position of said outputmeans as a function of the intensity of scene light, at least when theapparatus is used in daylight, said arrangement further including anauxiliary circuit having switchover means operable to move from a firstto a second position in which said resistor means is respectivelydisconnected from and in circuit with said light meter means andoperating means for automatically operating said switchover means atleast when the intensity of scene light is below a predetermined valueso that said resistor means I then influences the position of saidoutput means, said operating means comprising electromagnet means whichundergoes a change in the condition thereof when the intensity of scenelight is below said predetennined value to thereby operate saidswitchover means.

2. A combination as defined in claim 1, wherein said auxiliary circuitfurther comprises blocking means operative to adjust said shutter unitso that the latter furnishes a predetermined exposure time when theintensity of scene light is below said predetermined value.

3. A combination as defined in claim 1, wherein said auxiliary circuitfurther includes a switching circuit for said operating means.

4. A combination as defined in claim 1, wherein said switchover meanscomprises at least one electric switch.

5. A combination as defined in claim 1, wherein said arrangement furthercomprises a pair of normally open seriesconnected switches arranged tocomplete said auxiliary circuit in response to closing thereof, andfurther comprising a source of artificial light movable to an operativeposition to thereby close one of said switches and camera release meansmovable from a starting position to thereby close the other of saidswitches.

6. In a photographic apparatus for use in daylight and artificial light,a combination comprising adjustable diaphragm and shutter units; lightmeter means having output means movable between a plurality ofpositions; adjusting means providing an operative connection betweensaid light meter means and at least one of said units to adjust thelatter as a function of the position of said output means; variableresistor means; focusing means movable between a plurality of positionseach of which is indicative of a different distance from the subject andarranged to adjust said resistor means as a function of the selectedposition thereof; and an electric circuit arrangement including saidlight meter means and further including first photosensitive receivermeans in circuit with said light meter means to determine the positionof said output means as a function of the intensity of scene light, atleast when the apparatus is used in daylight, said arrangement furtherincluding an auxiliary circuit having switchover means operable to movefrom a first to a second position in which said resistor means isrespectively disconnected from and in circuit with said light metermeans and operating means for operating said switchover means at leastwhen the intensity of scene light is below a predetermined value so thatsaid resistor means then influences the position of said output means,said operating means including second photosensitive receiver means andsaid focusing means comprising masking means operative to determine theextent of exposure of said second receiver means to scene light as afunction of the position of said focusing means 7. In a photographicapparatus for use in daylight and artificial light, a combinationcomprising adjustable diaphragm and shutter units; light meter meanshaving output means movable between a plurality of positions; adjustingmeans providing an operative connection between said light meter meansand at least one of said units to adjust the latter as a function of theposition of said output means; variable resistor means; focusing meansmovable between a plurality of positions each of which is indicative ofa different distance from the subject and arranged to adjust saidresistor means as a function of the selected position thereof; and anelectric circuit arrangement including said light meter means andfurther including photosensitive receiver means in circuit with saidlight meter means to determine the position of said output means as afunction of the intensity of scene light, at least when the apparatus isused in daylight, said arrangement further including an auxiliarycircuit having switchover means operable to move from a first to asecond position in which said resistor means is respectivelydisconnected from and in circuit with said light meter means andoperating means for operating said switchover means at least when theintensity of scene light is below a predetennined value so that saidresistor means then influences the position of said output means, saidoperating means comprising electromagnet means whose condition ofenergization changes when the intensity of scene light is below saidpredetermined value and blocking means actuated by said electromagnetmeans in response to said change in the condition of said electromagnetmeans to thereby adjust said shutter unit for a predetermined exposuretime.

8. In a photographic apparatus for use in daylight and artificial light,a combination comprising adjustable diaphragm and shutter units; lightmeter means having output means movable between a plurality ofpositions; adjusting means providing an operative connection betweensaid light meter means and at least one of said units to adjust thelatter as a function of the position of said output means; variableresistor means; focusing means movable between a plurality of positionseach of which is indicative of a difierent distance from the subject andarranged to adjust said resistor means as a function of the selectedposition thereof; and an electric circuit arrangement including saidlight meter means and further including first photosensitive receivermeans in circuit with said light meter means to determine the positionof said output means as a function of the intensity of scene light, atleast when the apparatus is used in daylight, said arrangement furtherincluding an auxili circuit having switchover means operable to movefrom a firs to a second position in which said resistor means rsrespectively disconnected from and in circuit with said light metermeans, operating means for operating said switchover means at least whenthe intensity of scene light is below a predetermined value so that saidresistor means then influences the position of said output means, andsecond photosensitive receiver means exposed to scene light, saidoperating means including means for comparing the resistance of saidsecond receiver means with the resistance of said resistor means.

9. A combination as defined in claim 8, wherein said auxiliary circuitis a bridge circuit having a first branch including said second receivermeans and a second branch including said resistor means.

10. A combination as defined in claim 9, wherein said bridge circuitfurther includes a diagonal branch and said comprising means includestransistor means having a baseemitter circuit in said diagonal branch.

1. In a photographic apparatus for use in daylight and artificial light,a combination comprising adjustable diaphragm and shutter units; lightmeter means having output means movable between a plurality ofpositions; adjusting means providing an operative connection betweensaid light meter means and at least one of said units to adjust thelatter as a function of the position of said output means; variableresistor means having a resistance indicative of the guide number of thesource of artificial light which is to be used with the apparatus;focusing means movable between a plurality of positions each of which isindicative of a different distance from the subject and arranged toadjust said resistor means as a function of the selected positionthereof so that the resistance of the thus adjusted resistor means isindicative of the position of said focusing means and of said guidenumber; and an electric circuit arrangement including said light metermeans and further including photosensitive receiver means in circuitwith said light meter means to determine the position of said outputmeans as a function of the intensity of scene light, at least when theapparatus is used in daylight, said arrangement further including anauxiliary circuit having switchover means operable to move from a firstto a second position in which said resistor means is respectivelydisconnected from and in circuit with said light meter means andoperating means for automatically operating said switchover means atleast when the intensity of scene light is below a predetermined valueso that said resistor means then influences the position of said outputmeans, said operating means comprising electromagnet means whichundergoes a change in the condition thereof when the intensity of scenelight is below said predetermined value to thereby operate saidswitchover means.
 2. A combination as defined in claim 1, wherein saidauxiliary circuit further comprises blocking means operative to adjustsaid shutter unit so that the latter furnishes a predetermined exposuretime when the intensity of scene light is below said predeterminedvalue.
 3. A combination as defined in claim 1, wherein said auxiliarycircuit further includes a switching circuit for said operating means.4. A combination as defined in claim 1, wherein said switchover meanscomprises at least one electric switch.
 5. A combination as defined inclaim 1, wherein said arrangement further comprises a pair of normallyopen series-connected switches arranged to complete said auxiliarycircuit in response to closing thereof, and further comprising a sourceof artificial light movable to an operative position to thereby closeone of said switches and camera release means movable from a startingposition to thereby close the other of said switches.
 6. In aphotographic apparatus for use in daylight and artificial light, acombination comprising adjustable diaphragm and shutter units; lightmeter means having output means movable between a plurality ofpositions; adjusting means providing an operative connection betweensaid light meter means and at least one of said units to adjust thelatter as a function of the position of said output means; variableresistor means; focusing Means movable between a plurality of positionseach of which is indicative of a different distance from the subject andarranged to adjust said resistor means as a function of the selectedposition thereof; and an electric circuit arrangement including saidlight meter means and further including first photosensitive receivermeans in circuit with said light meter means to determine the positionof said output means as a function of the intensity of scene light, atleast when the apparatus is used in daylight, said arrangement furtherincluding an auxiliary circuit having switchover means operable to movefrom a first to a second position in which said resistor means isrespectively disconnected from and in circuit with said light metermeans and operating means for operating said switchover means at leastwhen the intensity of scene light is below a predetermined value so thatsaid resistor means then influences the position of said output means,said operating means including second photosensitive receiver means andsaid focusing means comprising masking means operative to determine theextent of exposure of said second receiver means to scene light as afunction of the position of said focusing means.
 7. In a photographicapparatus for use in daylight and artificial light, a combinationcomprising adjustable diaphragm and shutter units; light meter meanshaving output means movable between a plurality of positions; adjustingmeans providing an operative connection between said light meter meansand at least one of said units to adjust the latter as a function of theposition of said output means; variable resistor means; focusing meansmovable between a plurality of positions each of which is indicative ofa different distance from the subject and arranged to adjust saidresistor means as a function of the selected position thereof; and anelectric circuit arrangement including said light meter means andfurther including photosensitive receiver means in circuit with saidlight meter means to determine the position of said output means as afunction of the intensity of scene light, at least when the apparatus isused in daylight, said arrangement further including an auxiliarycircuit having switchover means operable to move from a first to asecond position in which said resistor means is respectivelydisconnected from and in circuit with said light meter means andoperating means for operating said switchover means at least when theintensity of scene light is below a predetermined value so that saidresistor means then influences the position of said output means, saidoperating means comprising electromagnet means whose condition ofenergization changes when the intensity of scene light is below saidpredetermined value and blocking means actuated by said electromagnetmeans in response to said change in the condition of said electromagnetmeans to thereby adjust said shutter unit for a predetermined exposuretime.
 8. In a photographic apparatus for use in daylight and artificiallight, a combination comprising adjustable diaphragm and shutter units;light meter means having output means movable between a plurality ofpositions; adjusting means providing an operative connection betweensaid light meter means and at least one of said units to adjust thelatter as a function of the position of said output means; variableresistor means; focusing means movable between a plurality of positionseach of which is indicative of a different distance from the subject andarranged to adjust said resistor means as a function of the selectedposition thereof; and an electric circuit arrangement including saidlight meter means and further including first photosensitive receivermeans in circuit with said light meter means to determine the positionof said output means as a function of the intensity of scene light, atleast when the apparatus is used in daylight, said arrangement furtherincluding an auxiliary circuit having switchover means operable to movefrom a first to a second position in which said resistor means isrespectively disconnected from and in circuit with said light metermeans, operating means for operating said switchover means at least whenthe intensity of scene light is below a predetermined value so that saidresistor means then influences the position of said output means, andsecond photosensitive receiver means exposed to scene light, saidoperating means including means for comparing the resistance of saidsecond receiver means with the resistance of said resistor means.
 9. Acombination as defined in claim 8, wherein said auxiliary circuit is abridge circuit having a first branch including said second receivermeans and a second branch including said resistor means.
 10. Acombination as defined in claim 9, wherein said bridge circuit furtherincludes a diagonal branch and said comparing means includes transistormeans having a base-emitter circuit in said diagonal branch.